A setup joint system may be used to position a device, such as a robotic arm, in an initial position. Such systems may also be known as pre-positioning systems. A setup joint system should allow the device to be moved freely in space so it can be located as necessary and then rigidly locked in the initial position for use.
Setup joint systems may be used in a robotic surgical system to position robotic surgical arms around a patient prior to surgery. In a robotic surgical system a surgeon manipulates robotic laproscopic surgical instruments robotically from a surgeon's console. The console provides a video screen that shows the instruments being manipulated at the surgical site. The console further provides master arms that the surgeon physically manipulates to operate the robotic laproscopic surgical instruments. It is desired to create the visual illusion that the surgeon is directly manipulating the surgical instruments so that the manipulations are intuitive and the presence of the robotic surgical system becomes transparent.
An important consideration for achieving a transparent and intuitive surgeon's console is providing good angular alignment of the remote robotic “hands” as seen on the viewing screen with the surgeon's real hands located on the master arms. If the setup joint system allows rotation of the supported robotic surgical arms, then position sensors are required to provide the angular orientation of the robotic surgical arms in the initial position in order to provide intuitive control to the surgeon. It is desirable that the setup joint system prevent rotation of the supported robotic surgical arms so that the angular orientation is fixed and the need for angular sensor input is eliminated.
A setup joint system for use in a robotic surgical system should be precisely counterbalanced to allow the operating room staff to easily position the robotic arm without risk of having the arm or setup joints collide with the patient. The system should be compact because space around the patient in an operating room is at a premium. The outboard weight of the system should be low to increase the stiffness and resonant frequency of the system.
It is desirable to mount the setup joint system to the operating table so that the possibility of relative movement between the setup joint system and the patient is reduced. Since the operating table may be tilted to improve patient access, a setup joint system that is mounted to the operating table should be gravity neutral so that it remains substantially balanced as it changes orientation relative to the direction of gravitational forces.